Here's something that should work for sure. Put the wiring to the starter just like you've had it for the last few months.

Now splice a wire to that wire you have at the starter. Then put the other end of that new wire into the E-14 plug where there is a B/R wire. That B/R should lead back to the ECU area and tie into the L/B wire on the ECU small plug.

Now do what you did previously. Backprobe the L/B at the ECU with your meter and go to Start with the key and see if you see 8-12vddc on the meter when you do that. It won't take but a moment with the key to Start to see the meter display the reading.

IF batt voltage shows up, then go start the car cold and see what happens.

I'm going to look at my 87wiring manual to over come my question about the E-14 wire colors.

 

Main Relay is in the area of the Trail coil assy. It's mounted on the fender area with a single screw/bolt if memory serves. Next to it should be a slightly smaller relay and that should be the Starter Cut Relay (controlled by the Theft Unit).

Starter cut relay is kinda shown in the attached jpg. Outboard of the trail coil assy and near a larger relay which is the MAIN RELAY.

 

Thanks Hailers, I'll give that a try. Let me run it down one more time though.

So I'm going to use a tap of some sort or find means of splicing my starter trigger wire with another wire which I will run to the black and red wire that's in the four prong gang plug with the reverse lights. Is this correct?

 

You got it. And after you do that, put your meter on 3B like you did once before and put the key to START. Voltage should show up on the meter when you turn to Start. That's to confirm we've got the right wire tapped into.

This seems simpler than anything else.

 

Well I went and bought some vampire taps at Radio Shack... these things rock! Made splicing the trigger wire in with that black/red wire like butter, though I used some spades and a bit of wire to extend the black/red wire without cutting or damaging anything to ensure a good solid connection. Backprobing the L/B (Black wire, blue stripe) on pin 3B on the ECU, I am now seeing nearly ten volts while CRANKING the engine over. Just to verify that I had tapped the proper wire and the results were for real, I disconnected the new splice at one of the spade connections and pulled readings again at the ECU while cranking...low and behold, I was only seeing the 1.something volts as I had before making the splice.

So yes, I am now seeing almost ten volts at the L/B wire while cranking, but unfortunately the engine was already warmed up when I did this. Stupid, I know, but I needed to go get gas because it was so dangerously low...it'd began to sputter at one point during testing!

Late tonight when I get home from the club I'll try cranking the car over now that supposedly she's got a good starting signal to the ECU. I am praying to the heavens above that the car starts without incident... I want so badly for this car to be reliable enough to be able to sell the Miata and get something that can haul and tow! AKA a Ford Expedition. Mmm...plasticy goodness.

I'll let you know later tonight, Hailers. Wish us luck!

 

Super. The reason I mention 8-12vdc at pin 3B........is because the starter really pulls the battery voltage down when you start any car and usually it's around 8-9vdc even lower on some cars.

I hope your cold starts will be much better now, because............I'm out of ideas. Sorry 'bout the water thermo sensor and buying a new one. You have spares now.

By the way, I think you can get a REAL good deal on Chrysler products now. Find one of those dealers that got "cut" and see if he has a bargain on a Dodge???? whatever their called truck/van. This recession isn't all that bad. Cars are cheap. Houses are cheap. Inflation is low. Bargains are out there for the 92% still working and have GOOD credit. humor

 

So I just got back from the drag show with my friend and it's actually pretty chilly out...went to fire up the car and crank crank crank crank FIRE! I dunno, it could be a fluke but I hope to god it's not! I *THINK*, I pray... that the car is FIXED! If that's the case, then Hailers, I will come to Texas and buy you some Starbucks and a new set of sockets some day lol

I really do appreciate your hard work, your advice, ideas, and most importantly; your tolerance.

Cross your fingers that she fires no prob again in the morning!

-Collin

 

Flawless! She starts beautifully!

I do think this thread should be archived, but the title modified. Such a strange problem!

 

I think this should be archived, but im so confused on the steps. Hey Acesanugal if you got time can you make a thread or write the whole thing you did? because just by reading what HAILERS wrote i dont know which one to touch especially on the ECU wiring stuff

 

What do you mean? Same issue?

The car in this thread would start up when HOT but not when the engine was cold.

The reason for that trait was his ECU was not seeing the START signal from the start circuit because he had done a transmission swap from automatic to manual which resulted in him bypassing the original start circuit and installing a different circuit which in turn did not allow the ECU to see the start signal.

He overcame that small problem by splicing another new wire to his start wire at the starter solenoid and putting the other end of that new wire into the plug called E-14 (a automatic transmission car only item) to mate with the original factory start signal to the ECU pin 3B.

He found out he had this problem by going to the ECU. He took his meter and pricked the wire at 3B which is L/B or Black with a Blue stripe on it on the lower row of wires and to the far right of that plug. You should see batt voltage when the key is held to Start. If not, then that poses a problem that needs fixing (unless you live in Honduras).

IF you have batt power at 3B, then the next thing to look for is approx 2-3 vdc on pin 2I (green/white wire in the middle plug, upper row, sort of in the middle). If you have 2-3vdc when the engine is cold and once the engine is HOT, you have 0.40 to a half volt dc on that wire, then there is nothing wrong with the water thermo sensor. If you have voltage at 3B and the voltage at 2I I just mentioned, then the problem isn't the same thing and what's wrong is * ANOTHER THING*.

'This FIX isn't for a car that is difficult to start when HOT but starts just fine COLD. Actually THAT problem can be over come by eliminating the start signal seen at 3B so the ECU uses the afm for starting fuel instead of the Start fuel map inside the ECU.

 

Actually Hailers, the car had this issue prior to the swap. However I do believe anyone interested in doing this swap should read here.